Telephone-exchange system.



No. 669,707. I Patented Mar. I2, I901.

C. E. SCRIBNER.

TELEPHONE EXCHANGE SYSTEM.

(Application flied Nov. 12, ,1894.)

(lo Muriel.)

CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE WESTERNELECTRIC COMPANY, OF SAME PLACE.

TELEPHONE-EXCHANGE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 669,707, dated March12, 1901.

Application filed November 12, 1894. Serial No. 528.526. (No model.)

To all whom it may con/06 nectionis made by means of the plugs is com-Be it known that I, CHARLES E. SORIBNER, plete at the substation theclearing-out ana a citizen of the United States, residing atChinunciator will display its signal.

cago, in the county of Cook and State of Illi- In this system theannunciator of a line is nois, have invented a certain new and usefulretained in position to conceal its indicator as Improvement inTelephone-Exchange Syslong as the telephonic apparatus at the subtems,(Case No. 361,) of which the following station is not in use, thecircuit of the signalis a full, clear, concise, and exact description,ing-battery through the line-annunciator bereference being had to theaccompanying ing then continuous. When the telephone 1o drawings,forming a part of this specificais brought into use, thesignaling-current is tion. automatically interrupted at the substation,

My invention relates to signaling appliwhereby the line magnet of theline-annunances for telephone-exchange systems; and ciator is deprivedof current and permits the it consists in improved apparatus forautoannunciator-signal to be displayed. Connec- 15 maticallytransmitting signals for connection tion is then made with the line bymeans of .and disconnection between substations and plugs in the usualway. The restoring-magthe central station or exchange. net of theannunciator is thereby excited and The system of my invention comprisesa again conceals the indicator or target of the source ofsignaling-current located at the exannunciator, while at the same timethe clear- 20 change; a group of line-wires connected in ing-outannunciator becomes connected in a common with the signaling-battery,each inbranch of the line-circuit. When the conneccluding asignaling-annunciator, the circuit tion is completed with the linecalled forthe of the signaling-battery through the line-Wireanswering-line the local circuit through and annunciator being normallyclosed at the restoring-magnet of the corresponding 25 each substation;means for opening the cirline-annunciator is closed, so that theoperacuit while the telephone at the substation is tion of theline-annunciator of the answerin use; a clearing-out annunciator adapteding-line when the telephone is brought into to be connected with twounited lines and use to answer is prevented. Upon the comconstructed togive a signal in response to pletion of conversation and the replacement8o 0 the completion of the circuit at the substaof the telephones upontheir switch-hooks at tion, and a device for preventing the operathesubstations the signaling-circuit is again tion of the line-annunciatorWhile a line is in closed. The clearing-out annunciator in a use. Theline-annunciator which I employ branch between the line and thesignalingand which, together with the circuits approbattery is thusexcited and displays its sig- 5 priate to it, constitutesafeature of myinvennal, which is interpreted as a signal for distion, comprises anindicator, a line-magnet connection. arranged to conceal the indicatorwhen it is My invention isillustrated in the accompaexcited, and anauxiliary restoring-magnet nying drawings. adapted to cause theindicator to be concealed Figure 1 of the drawings is a diagram repo 40independently of the action of the line-magresenting the generalorganization of the sysnet. The line-magnet of this annunciator is termas applied to a multiple s itchboard of included in the correspondingline-circuit, twosections,twosubstations beingshownconand the auxiliarymagnet, which I will designected with the exchange. Fig. 2 is a sidenate the restoring-magnet, is included in elevation of theline-annunciator. Fig. Sis a 5 4; a normally open local circuit which isautosimilar elevation of the clearing-out annunmatically closed at anyspring-jack in the act ciator which I employ.

of inserting a plug therein to connect with The apparatus atthesubstation-forexamthe line. The clearing-out annunciator is inplc, atsubstation A-comprises a telephone 1) cluded in a branch of thesignaling-battery and transmitter-b and a signal-bellb iu sepa- 50 totheconductor of the plug-circuit, so that rate branches from the line, anautomatic while the circuit of the line with which contelephoneswitch-hook I) being provided to ple switchboard, and includes theline-coil eof an annunciatorfupon the section d. The line after passingthrough the annunciatorcoil is grounded through a battery g, which iscommon to all lines of the exchange. Each spring-jack comprises threecontact-pieces-- a thimble h and two normally separated springs h and hThe thimble h is connected with the line conductor of the line, thespring -h' is grounded, and the spring b is connected,

through the restoring-coil e of annunciator)", with the terminal ofbattery 9.

The construction of annunciatorfis shown in Fig. 2. It comprises a coreupon which are wound two helices e and e, a shutter 6 which serves as anarmature for the core, and a light shield or indicator 6 which isadapted to be acted upon by the shutter e The shutter e is pivoted atits lower edge and a little to one side of its center of gravity ontrunnions e in i a bracket 6 forming part of the frame of theinstrument. Before the shutter is hung the shield e being pivoted at itsupper edge in an extension of the bracket. The shutter 6 carries aprojection which is adapted to engage the shield 6 near its pivotalpoint as the shutter falls outward and to throw the shield into a nearlyhorizontal position, whereby the face of the shutter e is displayed. Theshutter may bear any suitable number or other target upon its face.

As long as current exists in either helix 6 or e of the magnet the coreis magnetized and attracts the shutter to it, permitting the shield e tohang freely. When both magnets are unexcited, the shutter falls forwardand throws the shield into its horizontal position, as described.

The operators appliances for switching lines into connection with eachother and for performing the various operations involved in this are ofthe usual character. The connec'ting-plugs, however, are adapted for usein the particular form of spring-jack here employed. Each plug, as 't',comprises an insulated tip 2" and a shank 2' The tip is adapted to crosstogether the springs h if, while the shank makes connection with thethimble h. The shanks of the plugs t' and i which constitute a pair, areconnected together by a conductor 2, which includes the switch-contactsof a pair of calling-keys it and it, either of which when depressed isadapted to disconnect the corresponding plug from the other plug and. toconnect it with the terminal of a generator Z of signaling-currentadapted to operate the signal-bell b An operators telephone set an isconnected with the anvil of a listening-key n, by which the operator maybring her telephone into connection with conductor 2 of theplug-circuit.

In a branch from conductor 2 of the plugcircuit, extending to theterminal of battery 9, is included the clearing-out annunciator 0. Thisannunciator is represented in Fig. 3. It

comprises an electromagnet p, a pivoted armature or'shutter p, and ashield 19 The shutter 19 is pivoted at its lower edge, so as to falloutward when unattracted. The shield 19 hangs in front of shutter 17',being pivoted near its upper edge. It carries a short projection beyondits pivotal point, engaging with a hook upon the shutterp'. When theshutter, being unattracted, falls outward, shield 10 hangs freely initsvertical position; but when the shutter is attracted the hook engagesthe projection of the shield and cealed. When the telephone is removed fromthe hook, as shown in the drawings, the flow of the battery-currentis interrupted by condenser b Magnet 6 is t-husdev italized, shutterefalls outward, and shield e is raised and gives the signal of theannunciator. The attendant at section d, where annunciatorf is located,seeing this signal, inserts plug 2' in to the corresponding spring-jackc, at the'same time depressing her listening-key n to connect hertelephone with the circuit. Circuit from substation A is thus continuedthrough the operators telephone appliances m and she is placed incommunication with the call-initiating subscriber. At the same timesprings 71. 72, are crossed together, whereby the local circuit ofmagnet e is closed and the magnet, thus excited, retracts armaturee andefiaces the signal. The annunciator o is now con nected with the linethrough the medium of plug-circuit 2; but since the line-circuit is openat station A the annunciator does not display its indication. Theoperator having tested line to station A and found it free inserts plugi into spring-jack c of that line.

The local circuit through the restoring-magnet of annunciatorf of thatline is now closed. The operator signals the subscriber at station A bydepressing calling-key k, and. the subscriber, having responded, removesthe telephone from the switch-hook 19 The circuit from battery g throughmagnet e to earth at the substation is thus interrupted, but since themagnet e is still excited the annunciator is not operated. When thesubscribers have finished their conversation, either may replace histelephone 17 upon the switch-hook. The circuit from conductor 2 of theplug-circuit to earth at that substation is thereby completed. Currentfrom battery g flows through the magnet of clearing-out annunciator oandoperates it, thereby instantly displaying the signal for disconnect-ion.When the operator has removed the plugs from the spring-jacks, all thecircuits are returned to their normal condition.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- 1. In combination, an indicator adapted when releasedto display a signal, two electromagnets adapted to act independentlyupon said indicator to prevent its display, a normally-closed circuitcontaining one of said electromagnets and means for interrupting thesaid circuit, and a normally-open circuit containing theotherelectroinagnet and means for closing the same circuit,substantially as described.

2. In combination in an annunciator,a shutter adapted to fall to give asignal, two electromagnets acting independently upon the shut ter toprevent its fall, a normally-closed telephone-circuit including one ofsaid magnets and means for interrupting the said circuit, and anormally-open local circuit containing the other magnet and means forclosing said circuit, substantially as described.

3. The combination with a telephone-line,

means for producing current in the line, and

a switch adapted to interrupt the current during the use of thetelephone, of an annunciator and a target controlled thereby adapted tobe displayed when the annunciator-magnet is inert,an auxiliary windingon the said magnet, a local circuit therethrough, and means for closingthe local circuit in making connection. with the line, a clearing-outannunciator adapted to display a signal when excited, and means forbringing the clearingout annunciator into connection with the line,

as described.

4. In combination with a normally-continuous telephone-line, anannunciator having an indicator and two electromagnets adapted to actindependently upon the indicator to prevent its display, one of saidelectromagnets being included together with a source of current in thetelephone-line, a normally-open local circuit including the other magnetand a source of current, and switch contacts adapted to close the localcircuit when connection is made with the line, substantially asdescribed.

5. In combination with a normally-continuous telephone-circuit extendingfrom a substation to an exchange, a switch at the substation adapted toopen the line during the use of the telephone, spring-jacks connectedwith the line at the exchange, an annunciator having an indicator andtwo electromagnets each adapted to prevent the display of the indicator,one of the magnets being included together with a source ofsignalingcurrent in the telephone-line,a normally-open local circuitincluding the other magnet of the annunciator, and switch-contactsadapted to close the local circuit at any spring-jack when connection ismade therewith, substantially as described.

6. The combination with an elec'tromagnet of an armature-shutter pivotedat its lower edge and adapted to fall outward when unattracted, of apivoted shield suspended before the shutter, an arm projecting beyondthe pivotal point of the shield, and a projection upon the shutteradapted to engage the arm to throw the shield into a horizontalposition, as described.

7. The combination with a telephone-circuit extending from a substationto an exchange and closed at the substation through a circuit of highresistance, a switch at the substation adapted to close the line duringthe disuse of the telephone through a circuit of lower resistance, anannunciator having two electromagnets adapted to act independently onits indicator to prevent the display thereof, one of said magnets beingincluded together with a source of current in the telephone-circuit, andthe other being included with a source of current in a closed localcircuit, a clearing-out annunciator adapted to give a signal when itsmagnet is excited temporarily included with a source of current in abranch between the sides of the telephone-circuit, and means for openingthe 10- cal circuit when the clearing-out annunciator is disconnected,substantiall y as described.

8. The combination with an electromagnet and its armature, of a pivotedshield depending before the face of the armature and hid ing the same,and a hook carried by the armature, adapted to engage said shield nearits pivotal point, thereby causing the display of the target or face ofthe armature when the armature is attracted, substantially as described.

9. The combination with an electromagnet and the armature thereofpivoted at its lower edge, of a shutter depending before the armaturefrom its upper edge adjacent to the armature, an extension of theshutter above its pivotal point, and a hook carried by the armatureengaging said extension, substantially as described.

In witness whereof I hereunto subscribe my name this th day of August,A. D. 1894.

CHARLES E. SORIBNER. lVitnesses:

THOMAS D. LOOKWOOD, V. M. BERTHOLD.

